The present invention relates to a thermoplastic elastomeric resin composition and a process for the preparation thereof.
The present composition may be added as a softening agent to a thermoplastic elastomer such as polyester type resins, polyolefine type resins, plyurethane type resins, vinyl aromatic type resins and polyamide type resins.
Thermoplastic elastomeric resins which are rubber-like materials, do not need a vulcanization process and have thermoplastic resin-like molding processability are attracting attention in the fields of auto parts, parts for electric appliances, electric wire insulation, footwears and general goods.
Various types of such thermoplastic elastomeric resins have been developed and put on sale, such as polyolefine type, polyurethane type, polyester type, polystyrene type, polyvinyl chloride type and polyamide type.
Among those, polystyrene type thermoplastic elastomeric resins such as styrene-butadiene block copolymers (SBS) and styrene-isoprene block copolymers (SIS) and hydrogenated resins thereof have high softness and good rubber elasticity at normal temperature. Further, thermoplastic elastomeric resin compositions obtained from these show good processability.
However, these polymers have problems in resistance to weathering as they have double bonds in conjugated diene blocks in molecule.
To overcome the problems, the double bonds in block copolymers of styrene and conjugated diene are hydrogenated to give elastomeric resins with improved thermal stability.
Several thermoplastic elastomeric resin compositions of such hydrogenated ones have been proposed, for instance, in Japanese Patent Application Laid-Open (hereinafter refereed to as JP Laid-Open) Nos. 50-14742/1975 and 52-26551/1977. As modification of these, JP Laid-Open Nos. 58-13203211983, 58-145751/1983, 59-53548/1984 and 62-48757 disclose compositions comprising a hydrogenated styrene-conjugated diene block copolymer, a hydrocarbon and an alpha-olefin polymeric resin, and a process for the preparation thereof.
Unfortunately, the thermoplastic elastomeric resin compositions of the prior art comprising such hydrogenated block copolymers have a drawback in rubber properties, such as deformation under heat and pressure (compression set) and rubber elasticity at a high temperature.
To solve such a drawback, there have been proposed a cross-linking composition in which a silane compound is added to a composition containing such a hydrogenated block copolymer, and cross-linked one obtained by cross-linking a composition containing such a hydrogenated block copolymer in the presence of an organic peroxide, for instance, in JP Laid-Open Nos. 59-6236/1984 and 63-57662/1987, Japanese Patent Publication Nos. 3-49927/1991,3-11291/1991 and 6-13628/1994.
However, such proposed cross-linked compositions of the hydrogenated block copolymer are unsatisfactory in compression set at a high temperature, particularly at 100xc2x0 C. and, moreover, tensile properties deteriorate considerably at 80xc2x0 C. or more. Further, such compositions do not meet the levels of properties required in the fields of vulcanized rubber. Particularly, good processability cannot be attained, and the mechanical strength is low.
To solve such drawbacks, in JP Laid-Open No. 4-20549/1992, there is desclosed a polymer in which a component composed of carboxylic acid derivatives and/or epoxy derivatives is copolymerized with or graft polymerized to such a block copolymer, or in which other polymers are graft or block bonded to such a block copolymer, and, further, a polyamide type polymer and/or polyester type polymer are added to a composition of a hydrogenated block copolymer, and crosslinked in the presence of an organic peroxide.
However, the crosslinked composition of the hydrogenated block copolymer desclosed has problems. That is, compression set at a high temperature, particularly at 100xc2x0 C. or more is high and tensile properties are poor. Further, balance between compression set and hardness is bad.
In addition, in the case of blending polyamide type polymer, polyester type polymer and/or polyurethane type polymer, hardness is not less than HSA 85, which is little different from that of polyamide type polymer, polyester type polymer or polyurethane type polymer.
In JP Laid-Open Nos. 1-139241/1989 and 3-100045/1991, there is desclosed a melting blended substance of a thermoplastic elastic body selected from hydrogenated SBS block copolymers, olefin type elastomers, diene type elastomers, urethane type elastomers and plasticized polyvinyl chlorides and a polyester type thermoplastic elastomer or a polyether block amide.
However, this composition is poor in balance between compression set and hardness and shows unsufficient compatibility, so that the abrasion resistance is bad.
Further, JP Laid-Open No. 5-214209/1993 discloses a composition in which a modified polystyrene type resin and/or a modified polyolefin type resin having an epoxy, acid anhydride or oxazoline group is added to a composition containing a hydrogenated derivative of a block copolymer and a polyester typer resin, whereby the composition is improved in compatibility and excellent in softness, heat resistance and chemical resistance. JP Publication No. 5-75016/1993 (i.e., Laid Open No. 1-230660/1998) discloses a composition which comprises a hydrogenated derivative of a block copolymer and a hydrogenated derivative having a carboxylic acid group or a derivative group thereof together with a polyolefin resin and a thermoplastic polyester. JP Laid-Open Nos. 3-234745/1991, 3-234755/1991, 5-171003/1993 and 7-126474/1995 disclose a composition which comprises a hydrogenated derivative of a block copolymer and a hydrogenated derivative having a carboxylic acid group or a derivative group thereof together with a thermoplastic polyurethane. JP Laid-Open No. 2-97554/1990 discloses a composition which comprises a hydrogenated derivative of a block copolymer and a hydrogenated derivative having an epoxy group or a derivative group thereof together with a thermoplastic polyurethane.
However, those components have drawbacks. That is, compression set at a high temperature, particularly at 100xc2x0 C. or more is high and tensile properties are poor. In addition, balance between the compression set and hardness is bad.
Although, the aforesaid compositions are excellent in initial chemical resistance, they swell extremely and cannot maintain its form in long time dipping or dipping at 100xc2x0 C. or more, because such treatment as crosslinking is not carried out on a soft segment of the hydrogenated block copolymer.
A purpose of the invention is to provide a process for the preparation of a thermoplastic elastomeric resin composition which is soft and excellent in heat deformation resistance, mechanical strength, moldability, processability, particularly, oil resistance and stain resistance.
Another purpose of the invention is to provide such a thermoplastic elastomeric resin composition.
Thus, the invention provides a process for the preparation of a thermoplastic elastomeric resin composition comprising melt kneading
(a) 100 parts by weight of a block copolymer consisting of at least two polymeric blocks (A) composed mainly of a vinyl aromatic compound and at least one polymeric block (B) composed mainly of a conjugated diene compound, and/or a hydrogenated block copolymer obtained by hydrogenating said block copolymer,
(b) 20 to 300 parts by weight of a non-aromatic softening agent for rubber,
(c) 1 to 150 parts by weight of a peroxide-crosslinking type olefinic resin and/or a copolymeric rubber containing said resin, and
(d) 10 to 150 parts by weight of a peroxide-decomposing type olefinic resin and/or a copolymer containing said resin,
characterized in that the process comprises a step of heat-processing component (a), component (b), at least a part of component (c), at least a part of component (d) and at least a part of 1.0 to 1,200 parts by weight of component (e) in the presence of an organic peroxide to cause crosslinking, wherein component (e) is at least one thermoplastic polymer selected from the group consisting of polyester type (co)polymers, polyamide type (co)polymers and polyurethane type (co)polymers, and a subsequent step of blending these with the remaining part of component (c), and the remaining part of component (d) and component (e), if any. This process will be hereinafter referred to as process (P-1).
In a preferred embodiment, component (c) is one which is modified with a carboxyl, acid anhydride, epoxy or oxazolinyl group.
In another preferred embodiment, (f) 0 to 100 parts by weight of a hydrogenated petroleum resin are further blended before said heat-processing.
In another preferred embodiment, (g) 0 to 100 parts by weight of an inorganic filler are blended in any step.
In another preferred embodiment, at least 3 parts by weight of component (d) are subjected to said heat-processing in the presence of an organic peroxide and at least 5 parts by weight of component (d) are blended after said heat-processing.
In another preferred embodiment, at least 1 part by weight of component (c) is subjected to said heat-processing.
In another preferred embodiment, at least 10 parts by weight of component (e) are subjected to said heat-processing.
In another preferred embodiment, the crosslinking is carried out in the presence of a crosslinking aid which is a monomer having an ethylenically unsaturated group.
In another preferred embodiment, the organic peroxide is used in an amount of 0.1 to 4.0 parts by weight.
The invention also provides a thermoplastic elastomeric resin composition comprising
(a) 100 parts by weight of a block copolymer consisting of at least two polymeric blocks (A) composed mainly of a vinyl aromatic compound and at least one polymeric block (B) composed mainly of a conjugated diene compound, and/or a hydrogenated block copolymer obtained by hydrogenating said block copolymer,
(b) 20 to 300 parts by weight of a non-aromatic softening agent for rubber,
(c) 1 to 150 parts by weight of a peroxide-crosslinking type olefinic resin and/or a copolymeric rubber containing said resin, and
(d) 10 to 150 parts by weight of a peroxide-decomposing type olefinic resin and/or a copolymer containing said resin,
characterized in that said composition further comprises
(e) 1.0 to 1,200 parts by weight of at least one polymer selected from the group consisting of polyester type (co)polymers, polyamide type (co)polymers and polyurethane type (co)polymers, and component (c) is modified with a group which is able to react with a hydroxyl, carboxyl or amino group. This composition will be hereinafter referred to as composition (C-1).
In a preferred embodiment, component (c) is one which is modified with a carboxyl, acid anhydride, epoxy or oxazolinyl group.
In another preferred embodiment, the composition further comprises (f) 0 to 100 parts by weight of a hydrogenated petroleum resin.
In another preferred embodiment, the composition further comprises (g) at most 100 parts by weight of an inorganic filler.
In another preferred embodiment, the composition further comprises 0.1 to 10 parts by weight of a crosslinking aid which is a monomer having an ethylenically unsaturated group.
Another purpose of the invention is to provide a process for the preparation of a thermoplastic elastomeric resin composition which is soft and excellent in heat deformation resistance, moldability, particularly, oil resistance and abrasion resistance, and in mechanical properties at high temperatures.
Further purpose of the invention is to provide such a thermoplastic elastomeric resin composition.
The present inventors have now found the following. If component (d), peroxide-decomposing type olefinic resin and/or a copolymer containing said resin, is melt kneaded all in step (I) which will be mentioned below, most of (d) is decomposed by the molecule cutting action of an organic peroxide. Therefore, the flowability of the composition is extremely decreased and homogeneous dispersion of other components can not be obtained. Accordingly, physical properties, such as tensile properties, are decreased and delamination is observed in the elastomeric composition obtained. Meanwhile, if component (d) is not blended at all in step (I), the flowability of the composition is not improved during melt kneading. Particularly, dispersion of component (a) is poor and, therefore, cross linking cannot be carried out in a good dispersing state, which causes deterioration in physical properties such as tensile properties or delamination in the elastomeric composition obtained.
Meanwhile, if allocated parts of component (d) are blended and melt kneaded in steps (1) and (11), the deterioration in the physical properties mentioned above does not occure in the elastomeric composition obtained, and good appearance, adjustment of hardness and shrinkage factor may be effectively achieved as envisaged by blending component (d).
Then, the invention further provides a process for the preparation of a thermoplastic elastomeric resin composition comprising melt kneading
(a) 100 parts by weight of a block copolymer consisting of at least two polymeric blocks (A) composed mainly of a vinyl aromatic compound and at least one polymeric block (B) composed mainly of a conjugated diene compound, and/or a hydrogenated block copolymer obtained by hydrogenating said block copolymer,
(b) 20 to 240 parts by weight of a non-aromatic softening agent for rubber, and
(d) 5 to 100 parts by weight of a peroxide-decomposing type olefinic resin and/or a copolymeric rubber containing said resin,
characterized in that the process comprises the following steps:
(I) melt kneading the whole amounts of components (a) and (b) and the whole amounts of
(k) 1 to 30 parts by weight of liquid polybutadiene,
(l) 0.01 to 15 parts by weight of an unsaturated glycidyl compound or derivative thereof, and
(m) 0.01 to 15 parts by weight of an unsaturated carboxylic acid or derivative thereof, and a part of component (d), and, at the same time or subsequently, melt kneading these with the whole of
(h) 0.1 to 3.5 parts by weight of an organic peroxide per 100 parts by weight of a total amount of components (a), (b), (d) and (k), and
(II) melt kneading the product obtained from step (I) with the remaining part of component (d). This process will be hereinafter referred to as process (P-2).
In step (I) of the aforesaid present process, component (d) is decomposed by the action of (h) organic peroxide to enhance the flowability of the composition and, at the same time, to generate radicals which crosslink component (a) by a chain reaction and alternatively react with functional groups of other components. In step (II), component (d) is homogeneously dispersed in a matrix resin composed mainly of the crosslinked (a) to achieve the purposes of the present invention. Here, components (b) and (k), alone or by interacting with each other, give softness to the elastomeric composition obtained. Components (I) and (m) behave as a modifier to enhance a compatibilizing effect. An optional component (c) further enhances the crosslinking effect of component (a) under the action of (h) organic peroxide.
In a preferred embodiment, a weight ratio of the amount of component (d) blended in step (I) and that in step (II) is 10:90 to 90:10.
In another preferred embodiment, the whole of (c) at most 100 parts by weight of a peroxide-crosslinking type olefinic resin and/or a copolymeric rubber containing said resin are also melt kneaded first in step (I), where the amount of the organic peroxide (h) is 0.1 to 3.5 parts by weight per 100 parts by weight of a total amount of components (a), (b), (c), (d) and (k).
In another preferred embodiment, (i) 0.1 to 3.5 parts by weight of a crosslinking aid per 100 parts by weight of a total amount of components (a), (b), (d) and (k) are kneaded together with component (h) in step (I).
The invention also provides a thermoplastic elastomeric resin composition comprising
(a) 100 parts by weight of a block copolymer consisting of at least two polymeric blocks (A) composed mainly of a vinyl aromatic compound and at least one polymeric block (B) composed mainly of a conjugated diene compound, and/or a hydrogenated block copolymer obtained by hydrogenating said block copolymer,
(b) 20 to 240 parts by weight of a non-aromatic softening agent for rubber, and
(d) 5 to 100 parts by weight of a peroxide-decomposing type olefinic resin and/or a copolymeric rubber containing said resin,
characterized in that said composition further comprises
(k) 1 to 30 parts by weight of liquid polybutadiene,
(l) 0.01 to 15 parts by weight of an unsaturated glycidyl compound or derivative thereof, and
(m) 0.01 to 15 parts by weight of an unsaturated carboxylic acid or derivative thereof. This composition will be hereinafter referred to as composition (C-2).
In a preferred embodiment, the composition further comprises
(n) 10 to 1,500 parts by weight of at least one material selected from the group consisting of polyester (co)polymers, polyurethane (co)polymers, polyamide (co)polymers and polymethylpentene (co)polymers.
In another preferred embodiment, the composition further comprises (c) 0 to 100 parts by weight of a peroxide-crosslinking type olefinic resin and/or a copolymeric rubber containing said resin.
The present inventors have further found that when component (n) which will be described below is further blended, even if component (d) is kneaded all in step (I), it is possible to obtain a composition having various properties which is not inferior to those of the one prepared in the aforesaid processes (P-1 and P-2) and further to give good heat resistance to it.
The invention further provides a process for the preparation of a thermoplastic elastomeric resin composition comprising melt kneading
(a) 100 parts by weight of a block copolymer consisting of at least two polymeric blocks (A) composed mainly of a vinyl aromatic compound and at least one polymeric block (B) composed mainly of a conjugated diene compound, and/or a hydrogenated block copolymer obtained by hydrogenating said block copolymer,
(b) 20 to 240 parts by weight of a non-aromatic softening agent for rubber, and
(d) 5 to 100 parts by weight of a peroxide-decomposing type olefinic resin and/or a copolymeric rubber containing said resin,
characterized in that the process comprises the following steps:
(I) melt kneading the whole amounts of components (a), (b) and (d) and the whole amounts of
(k) 1 to 30 parts by weight of liquid polybutadiene,
(l) 0.01 to 15 parts by weight of an unsaturated glycidyl compound or derivative thereof, and
(m) 0.01 to 15 parts by weight of an unsaturated carboxylic acid or derivative thereof, or
the whole amounts of components (a), (b), (d), (k), (I) and (m) and the whole or a part of
(n) 10 to 1,500 parts by weight of at least one material selected from the group consisting of polyester (co)polymers, polyurethane (co)polymers, polyamide (co)polymers and polymethylpentene (co)polymers, and, at the same time or subsequently, melt kneading these with the whole of
(h) 0.1 to 3.5 parts by weight of an organic peroxide per 100 parts by weight of a total amount of components of (a), (b), (d) and (k), and
(II) further melt kneading the product obtained from step (I) with the remaining part of component (n), if any. This process will be hereinafter referred to as process (P-3).
In the above process, component (n) interacts with component (k) grafted to component (a) and functional groups of components (I) and (m), such as hydroxyl groups or carboxyl groups, to achieve the present effects.
For component (n), if use is made of a material of which melting point is much higher than that of the matrix resin, such as polymethylpentene or nylon-6, it is preferred to conduct the melt kneading for a longer time in order to disperse it homogeneously in the matrix resin. Such materials that have a comparatively high melting point decompose with difficulty and, therefore, do not cause deterioration in physical properties of the resin composition. It is rather preferred to blend and melt knead such materials in step (I) so as to disperse them homogeneously in the matrix resin.
Meanwhile, if, component (n) is a material of which melting point is not mush higher than that of the matrix resin, such a material decompose easily. Accordingly, when it is blended and melt kneaded in step (I), physical properties of the elastomeric resin composition obtained are decreased in some cases. Preferably, a most amount of such a material is blended and melt kneaded in step (II).
In a preferred embodiment, component (n) is polymethylpentene or nylon-6, and the whole or a part of component (n) is melt kneaded in step (I) or the whole of component (n) is melt kneaded in step (II) without melt kneading component (n) in step (I).
In another preferred embodiment, a part or none of component (n) is melt kneaded in step (I) and the remaining part of component (n) is melt kneaded in step (II).
In another preferred embodiment, a part or none of component (n) is melt kneaded in step (I) and the remaining part of component (n) is melt kneaded in step (II), wherein a weight ratio of component (n) blended in step (I) and that in step (II) is 10:90 to 0:100.
In another preferred embodiment, a part or none of component (n) is melt kneaded in step (I) and the remaining part of component (n) is melt kneaded in step (II), wherein component (n) is a thermoplastic polyester type elastomer, thermoplastic polyamide type elastomer or thermoplastic polyurethane type elastomer.
In another preferred embodiment, (i) 0.1 to 3.5 parts by weight of a crosslinking aid per 100 parts by weight of a total amount of components (a), (b), (d) and (k) are kneaded together with component (h) in step (l).
In another preferred embodiment, the whole of (c) at most 100 parts by weight of a peroxide-crosslinking type olefinic resin and/or a copolymeric rubber containing said resin are also melt kneaded first in step (I), where the amount of the organic peroxide (h) is 0.1 to 3.5 parts by weight per 100 parts by weight of a total amount of components (a), (b), (c), (d) and (k).